Modulation of impulsivity by topiramate: implications for the treatment of alcohol dependence.

Topiramate (TP), an anticonvulsant drug, has been widely used in the treatment of disorders characterized by impulsivity symptoms, so it goes to reason that it might be useful in addictive disorders. Recently, TP has been used to treat alcohol dependence, but it is still not known whether the effects of TP on alcohol consumption are related with its action on impulsivity. The aim of this preliminary study was to investigate which dimension of behavioral impulsivity is associated with the effects of TP. A 12-week, double-blind, placebo-controlled pilot study of TP for the treatment of alcohol dependence was conducted. Subjects were men recruited from alcoholism treatment units (TP = 31; placebo = 32). Diagnoses were made using the Structured Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Behavioral inhibition was assessed using the continuous performance test (CPT) and the stop-signal task. Differential reinforcement for low-rate responding (DRLR) was used to evaluate the delay-discounting dimension. Alcohol craving and alcohol consumption during the study were evaluated. Patients treated with TP presented lower rates of alcohol consumption in the number of drinks per drinking day (P < 0.05) and the number of heavy drinking days (P < 0.001). Scores on alcohol craving scales decreased significantly, and there was more improvement on the continuous performance test (total omissions and total commissions) and on the stop-signal task in the TP group than in the control group. Improved alcohol consumption behavior was associated with performance on the behavioral inhibition paradigm. The results of this study indicate that TP reduces drinking and that the mechanisms underlying this effect may involve, at least in part, modulation of the behavioral inhibition paradigm.